Valve housings of the type used in the construction of directional valves conventionally have been unitary structures, produced by casting processes. In these structures, all of the internal fluid passages are formed in the cast housing. If the valve is solenoid operated, solenoids may be attached to each end of the housing and centering springs placed in the housing between each solenoid and the valve spool.
One disadvantage of constructing a directional valve from a unitary housing, is that the fluid passages require that the housing be manufactured by casting which is a relatively expensive process compared to sintering or molding. Additionally, cast housing are relatively heavy. In solenoid operated valves in which centering springs are interposed between the solenoids and the valve spool, the length of the housing must be increased to provide space for the springs.
It is desireable to provide a lightweight housing for a directional valve which may be constructed economically by a process such as sintering or molding. Additionally, it is desireable to provide a solenoid operated valve in which the centering springs are not interposed between the solenoid and the spool such that the length of the housing may be reduced.